In the quest to comprehensively redesign the Silverado HD chassis to improve durability and ride, while also supporting increased capability, engineers developed 11 all-new, fully boxed frame assemblies. The frames have increased cross sections and use more high-strength steel for greater durability, higher towing capacity and improved ride and handling; the front sections are hydroformed.
The bending and beaming stiffness of the frames is increased 92 percent and 20 percent, respectively, with the fully boxed sections enhancing torsional stiffness by a factor of five. Also, larger engine and transmission mounts, coupled with a 125-percent-stiffer front frame structure, provide greater vibration control, while hydraulic body mounts are incorporated under the cab section on extended and crew cab models for a more isolated feel inside.
Engineers addressed common customer and aftermarket uses when designing the new frames, including adding access holes to the rear frame section to enable easier installation of fifth-wheel/gooseneck-style hitches. Also, the frame-mounted hitch for conventional trailering is stronger, with a box-tube design. It supports up to 16,000 pounds (7,257 kg).
The 2011 Silverado debuted at the Chicago International Auto Show this month with several new upgrades (11 to be exact) that are supposed to rocket the Silverado to the top of towing segments across the HD board. The list is as follows:
1. New Frame - "In the quest to comprehensively redesign the Silverado HD chassis to improve durability and ride, while also supporting increased capability, engineers developed 11 all-new, fully boxed frame assemblies. The frames have increased cross sections and use more high-strength steel for greater durability, higher towing capacity and improved ride and handling; the front sections are hydroformed.
The bending and beaming stiffness of the frames is increased 92 percent and 20 percent, respectively, with the fully boxed sections enhancing torsional stiffness by a factor of five. Also, larger engine and transmission mounts, coupled with a 125-percent-stiffer front frame structure, provide greater vibration control, while hydraulic body mounts are incorporated under the cab section on extended and crew cab models for a more isolated feel inside.
Engineers addressed common customer and aftermarket uses when designing the new frames, including adding access holes to the rear frame section to enable easier installation of fifth-wheel/gooseneck-style hitches. Also, the frame-mounted hitch for conventional trailering is stronger, with a box-tube design. It supports up to 16,000 pounds (7,257 kg)."
2. New and Improved Independent Front Suspension - "A completely redesigned independent front suspension system offers up to a 25-percent greater front axle weight rating – up to 6,000 pounds (2,721 kg) front gross axle weight rating (FGAWR) – enabling a snow plow to be used on all 4WD cab configurations with the available snow plow prep package, while also supporting improved ride and handling characteristics.
Silverado’s signature short-long arm/torsion bar front suspension design is retained, but now features new, forged steel upper control arms that are stronger and lighter than their predecessors. The new lower control arms are made of precision-machined cast iron to handle the greater loads. Five different torsion bar rates support five different front gross axle weight ratings (a single torsion bar was previously used for all models). This helps stabilize the range of trim heights of various models under load, while enhancing appearance, handling, durability, tire wear and alignment. The trim height is adjusted on each bar via a single bolt, easily allowing the height to be changed to account for the weight of a snow plow or other accessories.
The Silverado HD front suspension now uses a pair of urethane jounce bumpers on each side, instead of one, for improved load management; and there’s a new upper shock mount attachment design that’s positively connected to the frame with two fasteners. This design eliminates squeaks and clunks, while supporting higher load capability and increased durability.
Compared to competitors’ beam-axle front suspension, the Silverado’s independent front suspension provides a better ride, more accurate trim height control (with fewer parts) and greater flexibility to adjust the alignment for weight and tire sensitivity."
3. New asymmetrical leaf-spring rear suspension - "Commensurate with the Silverado HD’s greater strength and capability is a rear suspension designed to support greater loads. It features a new, larger asymmetrical leaf-spring design that also contributes to improved ride and handling characteristics.
The asymmetrical design is derived from unequal front and rear spring half lengths, which minimize axle hop and enhance traction control efficiency. 2500HD models feature a two-stage leaf-spring design, while 3500HD models have a three-stage design. All models feature 3-inch-wide (76 mm) leaf springs that are 20-percent wider than previous models.
The larger leaf-spring design supports increased rear gross axle weight ratings across the board. On the 2500HD models, the rating is 6,200 pounds (2,818 kg) – up from 6,084 (2,765). On 3500HD models, the rating increases to 7,050 pounds (3,204 kg) on single-rear-wheel models and 9,375 pounds (4,261 kg) on dual-rear-wheel models – the latter representing a nearly 14-percent increase over the previous 8,200-pound (3,727 kg) rating."
4. Segment-leading towing and payload capability - "Stronger frames, suspension systems with greater weight ratings and enhanced powertrain systems contribute to the Silverado HD’s class-leading towing and payload capability. The specifications charts included below outline capacities for each model and/or configuration, but here are the key facts:
* The maximum conventional (ball hitch) towing rating increases to 16,000 pounds (7,257 kg)
* A Silverado 3500HD crew cab/long box can tow up to 20,000 pounds (9,091 kg) with a fifth-wheel hitch. The 2010 Ram 3500 has a maximum rating of 17,600 pounds (8,000 kg) and the 2010 Ford F-350 is rated at a maximum of 18,800 pounds (8,545 kg). It should be noted that while Ford claimed segment-leading trailering and payload during its recent announcement of the 2011 Super Duty models, no towing ratings were issued
* The maximum payload (3500HD) is 6,335 pounds (2,873 kg) – that’s nearly 11 percent greater than the 2010 Ford F-350’s 5,730-pound (2,604 kg) rating and about 24 percent more than the 2010 Ram 3500’s 5,130-pound (2,331 kg) ratings. Again, while claiming segment-leading payload for the 2011 Super Duty models, Ford did not announce the ratings"
5. New Duramax and Allison Transmission combination - "Helping the new 2011 Silverado HD trucks deliver their best-in-class capabilities is a new version of the workhorse Duramax 6.6L diesel and Allison 1000 six-speed automatic transmission powertrain combination. The Duramax 6.6L is more powerful and durable and the Allison 1000 is stronger and helps enable new features, including the exhaust brake system. Together, this improved version of a proven combination is also expected to deliver segment-best fuel economy.
The Duramax 6.6L’s new and improved features include:
•Horsepower and torque expected to top previous model (testing is ongoing – check media.gm.com for updates)
•NOx emissions reduced at least 63 percent over 2010 models
•Quieter operation
•High-pressure (30,000 psi/2,000 bar) Piezo-actuated fuel system for greater fuel efficiency, improved performance and reduced emissions
•Exhaust brake system that enables controlled vehicle slowdown on downhill grades without actuating the brakes
•Selective catalytic reduction after-treatment system using diesel exhaust fluid (DEF) injection to provide the best overall diesel characteristics and performance – with a range of about 5,000 miles (8,000 km) between DEF refills
•Combustion and after-treatment have been optimized to provide about 700 miles (1,125 km) between diesel particulate filter regenerations – a 75-percent improvement over the previous system and significant contributor to improved fuel efficiency, as the regeneration process requires additional fuel
•B20 biodiesel capability for an alternative fueling option
•Internal revisions that improve durability
With nearly 1.3 million Duramax 6.6L engines produced since 2000, they have proven exceptionally durable and dependable. The internal elements that helped build its reputation are enhanced for 2011, including:
•Main bearings’ profiles changed to enhance oil film thickness
•Oil pump flow increased for increased pressure at low speeds
•The turbocharger’s oil circuit is changed to provide increased pressure at the turbo and faster oil delivery
•The connecting rods’ pin ends are modified to provide increased piston support
•New, higher-strength piston design that eliminates bushings to provide lower reciprocating weight
•An EGR cooler bypass reduces high-mileage soot deposits in the cooler and EGR circuit
The enhanced Allison 1000 for 2011 is strengthened to handle the higher torque capability of the new 6.6L Duramax engine, while also helping improve fuel economy and provide seamless assistance with a new exhaust brake system. Greater efficiency is delivered through reduced “spin loss” – meaning, the transmission channels more of the engine’s power to the axles, allowing it to do more with less fuel.
The Allison 1000 also features driver shift control with tap up/tap down shifting and a patented elevated idle mode cab warm-up feature. Also, the tow/haul mode reduces shift cycling for better control and improved cooling when towing or hauling heavy loads. The six-speed configuration retains its two overdrive gears for optimal efficiency.
Performance with the Duramax/Allison combination is also improved over previous models, with preliminary testing showing 0-60 mph times of less than 9 seconds and quarter-mile times of less than 16 seconds in 2500HD models. That’s about 0.3-second and 0.5-second quicker, respectively, than previous models."
6. New Vortec engine and six speed hyrda-matic powertrain - "The venerable Vortec 6.0L gas V-8 with variable valve timing returns to the new heavy-duty trucks, along with a strengthened version of the Hydra-Matic 6L90 six-speed automatic transmission. This combination delivers excellent performance and efficiency, with a greater emphasis on low-rpm power.
A new camshaft profile in the Vortec 6.0L helps the engine produce more torque lower in the rpm band, for improved launch feel and a greater feeling of overall performance at higher altitudes and when towing a trailer.
The 6L90 is enhanced for greater strength, smoothness and quietness via:
•Adding four attachment bosses to the transfer case adapter (4WD models) for increased strength and smoother, quieter performance
•Increasing the cross section size of the transfer case adapter for greater strength
•Adding a new, stronger output shaft
•Adding a new heat shield and vent hose"
7. Exhaust Brake System - "A new feature on Duramax-equipped models is an exhaust brake system. This driver-selectable feature uses the turbine control of the variable geometry turbocharger and the compression of the engine to generate backpressure, slowing the vehicle without applying the brakes. It is a smart system integrated with the cruise control feature and varies the braking to account for the grade and vehicle load.
The exhaust brake system allows for virtually effortless driving and towing, with seamless and quiet operation. It also helps prolong brake life and prevents overheating the brakes on long, downhill grades."
8. Larger Brakes - "Brake feel and performance is greatly improved with the 2011 Silverado HD trucks. The standard four-wheel disc system is completely revamped to deliver smoother, more immediate and confident-feeling performance. Four-wheel, four-channel ABS is standard on all single-rear-wheel models and a three-channel system is standard on dual-rear-wheel models.
The front and rear rotors are larger in diameter – 14 inches (355 mm) – and width on all models to support their increased capacity, weight ratings and trailering ratings, while the calipers are stiffer and stronger. The hydroboost brake booster calibration is revised for reduced pedal effort and the travel of the pedal is also revised for a more comfortable, confident feel.
Larger wheel hub and bearing assemblies complement the new brake system and the rear rotors attach to the wheel hubs for easier servicing."
9. Improved ride, handling, and steering - "Longer wheelbases – ranging from 133.6 inches (3,395 mm) to 167.7 inches (4,259 mm) – and wider front/rear tracks enhance the ride and handling characteristics of the Silverado 2500HD and 3500HD, giving them a greater feeling of smoothness and control.
The longer wheelbases and wider tracks are complemented by the new, stiffer frames, new jounce bumpers, shock mounts and hydraulic body mounts to provide a solid, smooth and isolated driving experience. New shocks were specially valved to support the new trucks’ weight ratings, while balancing excellent ride characteristics.
Also enhancing the driving experience is a revised steering system designed to support the trucks’ greater front gross axle weight rating. It includes a new, larger steering gear, power steering pumps and linkages. The pumps (different parts for gas and diesel models) deliver greater pressure for reduced steering effort in low-speed and parking maneuvers; they are also quieter. On some models, the new linkages feature a compliant joint added at the pitman attachment to enhance handling.
10. Comprehensive safety and functional technology - The 2011 Silverado 2500HD and 3500HD models have a comprehensive roster of safety features and functional technologies that include:
•StabiliTrak electronic stability control system on all single-rear-wheel models
•Larger, four-wheel disc brakes with standard four-wheel ABS
•A new high-strength steel tubular frame cross member that enhances safety and improves crashworthiness
•Seat pelvic/thorax and head curtain side air bags available on 2500HD
•Available rear backup camera
•Segment-exclusive OnStar 9.0
•Trailer sway control system on all single-rear-wheel models
•Hill start assist (standard on single-rear-wheel models)
Trailer sway control system provides an added measure of confidence when towing a trailer. The system senses conditions of trailer sway and intervenes with braking and/or reduced engine power to bring the trailer under control and keep it on its intended path. The system will use electric trailer brakes when a trailer is plugged into the standard wiring harness of the truck and its performance requires no input from the driver.
The hill start assist system is automatically engaged when sensors detect the vehicle is on grade of about 5 percent or greater. It holds the brakes for about 1.5 seconds or until the gas pedal is pressed, preventing rollback – it is particularly effective when towing, giving the driver time to switch from the brake pedal to the gas pedal without rolling."
11. Lives Bigger, drives better, and works harder - "From the available remote starting feature to the unimpeded access offered by the 170-degree-opening rear access doors on extended cab models, the 2011 Silverado HD models live bigger, drive better and work harder. The interiors are refined, with improved quietness and attention to detail, but designed for working. Numerous storage compartments provide covered access for everything from work gloves to laptops.
Indeed, for many owners the Silverado HDs are mobile workspaces, offering mobile WiFi, USB connectivity, Bluetooth connectivity, XM Satellite Radio and a navigation system. Multiple charge points enable multiple electronic devices to operate simultaneously; and when equipped with the available navigation system, XM NavTraffic offers real-time updates of traffic conditions (in selected areas) that can help plan the most effective route to the job site.
Cold-weather customers will appreciate the Duramax 6.6L’s quick, reliable start-up, with a starting time on par with gas engines. Its glow plug cycle time is the segment’s best in all temperatures, taking no more than 3 seconds in temperatures as low as -20 F (-29 C). There’s also a cab heat-up feature that allows the engine to idle faster in low temperatures to warm up the interior faster.
And when you’re on the road, the Silverado HDs take you farther without stopping. A new, 36-gallon (136 L) fuel tank is standard on all models and, with the improved fuel efficiency of the powertrains, enables a cruising range of up about 680 miles (1,090 km) with the Duramax 6.6L. That’s the equivalent of a trip from Houston to Oklahoma City and back to Dallas on a single tank.
Finally, all 2011 Silverado 2500HD and 3500HD trucks work under the best warranty coverage in Canada – five-year/160,000-kilometer limited powertrain warranty, plus roadside assistance, courtesy transportation and other features that provide assurance that Chevrolet backs its trucks confidently."
*All information and quotes taken from www.gminsidenews.com and the GM Press Release from the Chicago Auto Show*
